Potential Bahtinov cutter?

[Stefan Buda]

I purchased a 5W diode laser for my home brew CNC router and made a tiny cutting head for it. Interesting exercise designing such a cutting head after 20 years of designing cutting heads for kilowatt class lasers.
If I can cut 1mm thick plastic with it at fast enough speed, I should be able to make large Bahtinov masks up to 300mm diameter.

[Troy]

Good project Stefan. Is the 300mm the mask outer diameter or the pattern outer diameter.

Reason I ask is I have a mask needed in the near future for a 12.5" newtonian.

[Stefan Buda]

If I replace the spindle with the laser, I will have a cutting area of 308x308.

[billdan]

I presume you can control the heat produced by the laser so the plastic does not catch on fire.

[Stefan Buda]

Laser cutting is not supposed to be done the way it is seen on YouTube, in case that is where you got the idea of the fire. Lase cutting without a cutting head is for B-grade Hollywood movies. People don't seem to realize that laser cutting is a chemical process, in most cases, where the laser provides the energy to start and maintain the (oxidation) reaction and the assist gas (air) coming through the nozzle provides the oxigen and blows out the resulting smoke from the cut. All the burning should be confined within the narrow cut by the air jet. The question is whether 5W power is enough to cut plastic at at useful speed.